TeleGeography: Ethernet VPLS, EoDWDM interest grows, while IP/VPN expansion dips
HISTORICAL SPACE FREQUENCIES. The first satellite to orbit the Earth was Sputnik 1, launched by the Soviets in October 1957. It carried two radio beacons on frequencies of 20.005 and 40.01 MHz. The Soviets continued to use frequencies around 20 MHz and even some around 15 MHz for many subsequent missions. This tends to be used for uplinks of the satellites that downlink in the 137 - 138 MHz band. 2  149.95 - 150.05 MHz. 3  This is used by satellites providing positioning, time and frequency services, by ionospheric research and other satellites.
Most of the satellites in medium earth orbit circle the earth at approximately 6,000 to 12,000 miles above the earth in an elliptical orbit around the poles of the earth. Any orbit that circles around the poles is referred to as a 'polar orbit'.atellites in this orbital range also have a very small 'footprint'--that is, the surface of the earth that can be covered by the signal broadcast from the satellite is small. Thus, lots of satellites (35 or more) are required to make worldwide communication possible.